Identity formation is a key developmental task in adolescence. Although many adolescents in modern societies face issues of identity, there are substantial individual differences in identity exploration and commitment. Little is known about the origins of these individual differences. The current study investigated the genetic and environmental…

The study aimed to examine the factor structure of the Obsessive Beliefs Questionnaire (OBQ), the most widely used measure of dysfunctional beliefs in obsessive-compulsive disorder (OCD). Multiple exploratory methods (exploratory factor analysis, cluster analysis by variable, multidimensional scaling) were used to examine the questionnaire.…

Cross-cultural validity studies for psychological instruments may result in overestimation of structure invariance due to some items being scored on more than one scale. This problem, called the common-item effect, is investigated with some data from the literature. (JKS)

The Endler S-R Inventory of General Trait Anxiousness was analyzed employing Smallest Space Analysis (SSA) and factor analysis. The SSA yielded a two-dimensional lattice partitioning the space into regions corresponding to the situations specified in the inventory. The factor-analytic results were similar but not as informative. (Author/JAZ)

Geometric approaches to representing interrelations among tests and items are compared with an additive tree model (ATM), using 2,644 examinees and 2 other data sets. The ATM's close fit to the data and its coherence of presentation indicate that it is the best means of representing tests and items. (TJH)